1. Chapter 5 Lecture Slides
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2. Chapter 5-Integumentary System
What does integument mean?
covering
Components:
skin
hair
nails
glands

3. Functions 1. Protection: water loss, microbes, UV light 2. Sensation:
hot, cold, pain, pressure
3. Temperature regulation:
helps maintain homeostasis

4. 4. Excretion: removes waste 5
4. Excretion: removes waste 5. Vitamin D production: UV light stimulates production

5. Skin Facts Weighs 9 lbs. Used to determine body fat
2 main regions: epidermis and dermis

7. Epidermis 1st major skin region (outside)
Composed of stratified squamous epithelium
Keratinization:
- process in which new cells (with keratin) push
old cells to surface
days for new cells to reach surface

8. Strata of Epidermis Stratum corneum: - outermost layer of epidermis
layers of dead squamous cells filled with
keratin
- accounts for 75% of epidermal thickness
- dandruff is this layer flaking off scalp
Callus:
forms when stratum corneum has frequent friction

9. Stratum basale:
- deepest layer of epidermis
- single layer of cells
- firmly attached to dermis

10. Dermis 2nd major skin region Dense connective tissue
Contains collagen and elastic fibers
Contains fibroblasts, nerve endings, smooth muscle, glands, blood vessels, and hair follicles
Cleavage lines:
- area where skin is most resistant to stretching
- due to orientation of collagen fibers
- important in scarring

12. Layers of Dermis Papillary layer:
- thin connective tissue layer that contains blood
vessels
- Dermal papillae:
projections that extend up into epidermis
remove waste and help regulate body temp.
ridged on hands and feet (fingerprints)
pattern is genetically determined

13. Reticular layer:
- deepest layer of dermis
- accounts for 80% of dermis

15. Hypodermis Below dermis Foundation of skin
Attaches skin to underlying muscle and bone
Contains loose and adipose tissue
Contains ½ of body’s fat
Body fat for females 20-23%, males 13-25%

17. Skin Color and Variations
Determined by:
- pigments
- genetics
- blood circulation
- thickness of stratum corneum
Melanocytes of darker skinned people produce more and darker melanin than fairer skinned people
All races have same number of melanocytes

18. Skin Pigments Melanin: - produced by melanocytes
- ranges from yellow to reddish-brown to black
- responsible for hair and eye color
- provides protection against UV light
- amt. produced determined by genetics, UV light,
hormones
- freckles are accumulation of melanin
- albinism is absence of melanin

20. Carotene:
- yellow-orange pigment found in plants
- accumulates in stratum corneum
Hemoglobin:
- gives pinkish-red color
- found in red blood cells

21. Tanning and Sunburns
Exposure to UV light stimulates melanocytes to increase production of melanin
Melanin builds up to help protect skin against UV radiation (tan)
A sunburn is the skin reacting to UV exposure
UV light causes elastic fibers to clump and become leathery
UV light can alter DNA in cells causing them to mutate (cancer)

22. Skin Color and Disease Redness:
fever, hypertension, inflammation, allergies
Pallor:
anemia or low blood pressure
Jaundice:
liver disorder (yellow)
Bronzing:
Addison’s disease (kidney disease)
Bruising:
broken blood vessels

23. Hair Components Hair/shaft: flexible strands of keratinized cells
Root:
below skin (scalp)

24. Hair Bulb:
- base of root
- where hair is produced
Hair Follicle:
- group of cells that surround root and bulb
- gives hair different shapes

26. How is Hair Produced? Hair is produced in hair bulb
Hair bulb rests on blood vessels to supply it with nutrients
Hair grows longer as cells are added to base of
hair bulb

27. Hair Facts Testosterone and good nutrition promote hair growth
Growth occurs in cycles: active and resting
Scalp hair grows for 3 years and rests for 1 year
Eyelashes grow for 30 days and rest for 105 days
We lose about 90 scalp hairs/day
Grey hair is the loss or fading of melanin
Male pattern baldness is from the loss of the hair follicle

28. Hair Muscles Arrector Pili:
smooth muscle that surrounds each hair follicle
contracts and hair stands on end
(goose bumps)

29. Glands Sebaceous glands: - connected to hair follicle
- sebum: oily substance that lubricates hair and
skin to prevent drying
Eccrine sweat glands:
- all over body and open into sweat pores
- water and salt secretions

30. Apocrine sweat glands:
- open into hair follicle
- only in armpits and genitalia
- thick, rich secretions
- become active during puberty and cause
body odor

31. Nails
What are they?
thin plate with layers of dead stratum corneum cells with hard keratin

32. Nail Structure Nail body: visual part Nail root: covered by skin
Cuticle:
stratum corneum that extends into nail body

33. Nail matrix:
- continuation of nail root
- gives rises to most of nail
Nail bed:
attaches to nail and is distal to nail matrix
Lunula:
- part of nail matrix
- whitish, crescent shaped area
- base of nail

35. Vitamin D Production 1. UV light causes skin to produce a precursor
molecule of vitamin D
Precursor is carried by blood to liver where it is modified
Next to kidneys where it is modified again to form active vitamin D
Vitamin D can also be ingested through fish oils, fortified milk, eggs, and butter.
Vitamin D stimulates intestine to absorb calcium and phosphate (bone growth and muscle function)

36. Temperature Regulation
Body temp. should be 98.6oC
Rate of chemical reactions (metabolism) is altered by changes in temp.
To cool body:
blood vessels in dermis dilate and heat is transferred from deep in tissues to skin and sweat is produced
Too heat body:
blood vessels constrict to reduce blood flow to skin and heat is retained

38. Aging and the Integument
Blood flow decreases and skin becomes thinner due to decreased amounts of collagen
Decreased activity of sebaceous and sweat glands make temperature regulation more difficult
Loss of elastic fibers cause skin to sag and wrinkle

39. Classification of Burns
1st degree:
damages only epidermis
redness, slight swelling, pain
heals within 2-3 days (usually no scar)
includes sunburns or exposure to cold
2nd degree:
damages epidermis and upper dermis
redness, swelling, pain, blisters
heals in 2 weeks with some scarring

40. 3rd degree:
destroys epidermis and dermis
burned areas are cherry red to black
nerve endings are destroyed
skin graft might be necessary

42. Skin Cancer Most common cancer Mainly caused by UV light exposure
Fair-skinned people more prone
Prevented by limiting sun exposure and using sunscreens
UVA rays cause tan and is associated with malignant melanomas
UVB rays cause sunburns
Sunscreens should block UVA and UVB rays

43. Types of Skin Cancer Basal cell carcinoma:
- cells in stratum basale affected
- cancer removed by surgery
Squamous cell carcinoma:
- cells above stratum basale affected
- can cause death
Malignant melanoma:
- arises from melanocytes in a mole
- rare type

45. Skin Disorders

46. Skin cancer Affects 1 in 5 Americans Caused by UV damage to DNA Types:
Basal cell carcinoma
Least malignant, most common (80% skin cancers)
Stratum basale
Sun-exposed areas of face
Shiny, dome-shaped nodules
Slow-growing; rarely metastasizes (spreads)
Removal by surgery (99% cases)

47. Skin cancer Squamous cell carcinoma 2nd most common
Keratinocytes of stratum spinosum
Scaly, reddened bump
Grows rapidly and can metastasize if not removed
Removal by surgery or radiation therapy

48. Skin cancer Melanoma Most dangerous
Highly metastatic, resistant to chemotherapy
1/3 from moles (spreading brownblack patch)
Key = Early detection!!!
Surgery + immunotherapy

49. ABCD(e) Rule for skin cancer
A = Asymmetry: 2 sides of pigmented spot do not match
B = Border irregularity: blurry or jagged edges
C = Color: several colors (brown, black, tan, blue, red)
D = Diameter: >6mm in diameter (pencil eraser)
E = Elevation: raised above surface or uneven surface

51. burns Tissue damage caused by heat, electricity, radiation, chemicals
Main threat: loss of fluids (dehydration, electrolyte imbalance)
Kidney failure, circulatory shock
Treatment: replace fluids via IV
Rule of Nines: estimating extent of burns
Divide body into 11 areas
Each part is 9% of total body area + 1% genital region

52. Rule of nines

53. Classifying burns
1st-degree burns: only epidermis damaged  swelling, redness, pain (sunburn)
2nd-degree burns: injure epidermis & upper dermis  redness and pain; blisters
3rd-degree burns: entire thickness of skin, destroy nerve endings (no pain)  need skin graft

55. First-degree burn

56. second-degree burn

57. third-degree burn

58. Critical burns: >25% of body with 2nd degree burns
>10% of body with 3rd degree burns
3rd degree burns on face, hands, feet
Face: swelling of respiratory passages  suffocation
Joints: scar tissue formation limits mobility

59. Skin graft

60. Developmental Aspects of Skin
Fetus: downy coat of colorless hairs (lanugo)
At birth:
covered with white, cheesy substance (vernix caseosa) to protect skin in watery environment
Milia: white spots, accumulations in sebaceous glands (baby acne)

61. Developmental Aspects of Skin
Childhood: skin thickens; deposit subcutaneous fat
Adolescence: sebaceous glands activated (oilier hair and skin), acne appears

62. Developmental Aspects of Skin
Adults:
Environmental assaults (sun, wind, chemicals)
Old age: thin skin, less oil (dry skin), less fat, less elasticity, less hair (greying and balding)